Spinal-pelvic deformities, trauma, fractures, tumors, inflammation and degeneration can necessitate surgical intervention to secure bones to each other or implants to the bone. Implants such as rods and plates can be used to replace or augment bone. Fixation devices such as hooks, wires, screws and connectors can be used to secure the implants to bone or to connect boney elements together.
In the spinal-pelvic region, bone attachment of implants or fixation devices can be to the spinal column, sacrum bone or ilium bone. Known implants include spinal rods and plates. Fixation devices include iliac screws, sacral screws, and iliac-sacral screws which can be joined together or to spinal rods/plates by a variety of connectors. However, the sacrum has a thin cortical shell often with poor trabecular bone quality which limits screw length selection to the detriment of stable fixation. The ilium offers adequate fixation area but is not sufficient on its own as it may encounter problems of screw pullout and loosening over time. Screw pullout is mainly associated with the presence of a mobile sacro-iliac joint and with an offset distance between iliac screws and an implant placed in the lumbar and/or sacral spine. Moreover, current techniques of attempting to limit the extent of screw pullout have limited success and are surgically complex which can undesirably increase operating times.
Therefore, it is desired to overcome or reduce at least some of the above-described problems.